1. Field of the Invention
The present invention relates to two dimensional representations of objects and, more specifically, to decoys representing potential military targets used to confuse or distract military opponents.
2. Description of the Related Art
Armies and military organizations employ decoys that simulate field guns, tanks, aircraft, and other military targets, to distract enemy forces, confuse them as to the location, type and size of the deployer's forces, and to draw the enemy's fire thereby causing the enemy to futilely expend ammunition and to reveal the enemy's position. The known decoys vary in sophistication depending on the trade-off, among other things, of fidelity to the portrayed target, expected viewer range, ease of use, and cost. Some decoys are very realistic three-dimensional mock-ups that may be made of material reflective to radar and may be heated to simulate the infra-red signal of a simulated target.
Other useful decoys are two-dimensional mural graphic representations. These murals portray targets by presenting a likeness of the target consisting of a detailed, realistic artist's representation of the target or a photograph reproduced onto the two-dimensional surface. The two-dimensional surface may be rigid or may be of a flexible material suitable for folding or rolling-up. While not the ultimate in fidelity, two-dimensional mural decoys have substantial utility to armies because they are more portable, are easier to set-up and knock-down, and are cheaper than three dimensional decoys thereby constituting a smaller loss when shot-up or abandoned. Teledyne Brown Engineering produces a two-dimensional mural tank decoy with flexible backing and a collapsible, metal frame.
A drawback of prior art two-dimensional mural decoys is that their realism depends on their orientation to the sun. This aspect of two-dimensional mural decoys reduces their effectiveness during parts of the day and may restrict the deployer's options as to placement of the decoys. When existing two-dimensional mural decoys are frontlit, that is, when the sun is behind the observer, as illustrated in FIG. 1, they portray their simulated target relatively effectively. However, when existing two-dimensional mural decoys are backlit, that is, when the observer is facing the sun, as illustrated in FIG. 2, they are much less effective because horizontal surfaces of the portrayed target are not realistically portrayed.
When backlit, the sun reflects off the horizontal surfaces of a three-dimensional object causing them to appear significantly brighter to the observer facing the sun. These horizontal areas appear brighter as the sun approaches the horizon, and may appear to lose color and may appear as bright white or glare regions. This brightening phenomenon occurs to some extent without regard to the color or surface treatments of the horizontal areas of the object. The absence of bright or glare regions on backlit two-dimensional mural decoys is a significant cue to the intended observer that what they are observing is a decoy and not the real object.
Another drawback of prior art two-dimensional mural decoys is that they do not realistically portray the transition areas between lit surfaces and shadowed surfaces of backlit objects and they do not portray the change in contrast between lit surfaces and shadowed areas as the incidence of sunlight to the object changes through the course of the day.